Computers: History and Development

Nothing epitomizes modern life better than the computer. For better or
worse, computers have infiltrated every aspect of our society. Today computers
do much more than simply compute: supermarket
scanners calculate our grocery bill while keeping store inventory;
computerized telephone
switching centers play traffic cop to millions of calls and keep lines of
communication untangled; and
automatic teller
machines let us conduct banking transactions from virtually anywhere in the
world. But where did all this technology come from and where is it heading? To
fully understand and appreciate the impact computers have on our lives and
promises they hold for the future, it is important to understand their
evolution.

Early Computing Machines and Inventors

The abacus,
which emerged about 5,000 years ago in Asia Minor and is still in use today, may
be considered the first computer. This device allows users to make computations
using a system of sliding beads arranged on a rack. Early merchants used the
abacus to keep trading transactions. But as the use of
paper
and pencil spread, particularly in Europe, the abacus lost its importance.
It took nearly 12 centuries, however, for the next significant advance in
computing devices to emerge. In 1642,
Blaise
Pascal (1623-1662), the 18-year-old son of a French tax collector, invented
what he called a numerical wheel calculator to help his father with his duties.
This brass rectangular box, also called a Pascaline, used eight movable dials to
add sums up to eight figures long. Pascal's device used a base of ten to
accomplish this. For example, as one dial moved ten notches, or one complete
revolution, it moved the next dial - which represented the ten's column - one
place. When the ten's dial moved one revolution, the dial representing the
hundred's place moved one notch and so on. The drawback to the Pascaline, of
course, was its limitation to addition.

In 1694, a German mathematician and philosopher,
Gottfried
Wilhem von Leibniz (1646-1716), improved the Pascaline by creating a machine
that could also multiply. Like its predecessor, Leibniz's mechanical multiplier
worked by a system of gears and dials. Partly by studying Pascal's original
notes and drawings, Leibniz was able to refine his machine. The centerpiece of
the machine was its stepped-drum gear design, which offered an elongated version
of the simple flat gear. It wasn't until 1820, however, that mechanical
calculators gained widespread use. Charles Xavier Thomas de Colmar, a Frenchman,
invented a machine that could perform the four basic arithmetic functions.
Colmar's mechanical calculator, the arithometer, presented a more practical
approach to computing because it could add, subtract, multiply and divide. With
its enhanced versatility, the arithometer was widely used up until the First
World War. Although later inventors refined Colmar's calculator, together with
fellow inventors Pascal and Leibniz, he helped define the age of mechanical
computation.

The real beginnings of computers as we know them today, however, lay with an
English mathematics professor,
Charles
Babbage (1791-1871). Frustrated at the many errors he found while examining
calculations for the Royal Astronomical Society, Babbage declared, "I wish
to God these calculations had been performed by steam!" With those words,
the automation of computers had begun. By 1812, Babbage noticed a natural
harmony between machines and mathematics: machines were best at performing tasks
repeatedly without mistake; while mathematics, particularly the production of
mathematic tables, often required the simple repetition of steps. The problem
centered on applying the ability of machines to the needs of mathematics.
Babbage's first attempt at solving this problem was in 1822 when he proposed a
machine to perform differential equations, called a
Difference Engine.
Powered by steam and large as a locomotive, the machine would have a stored
program and could perform calculations and print the results automatically.
After working on the Difference Engine for 10 years, Babbage was suddenly
inspired to begin work on the first general-purpose computer, which he called
the Analytical Engine. Babbage's assistant,
Augusta Ada King,
Countess of Lovelace (1815-1842) and daughter of English poet
Lord Byron,
was instrumental in the machine's design. One of the few people who understood
the Engine's design as well as Babbage, she helped revise plans, secure funding
from the British government, and communicate the specifics of the Analytical
Engine to the public. Also, Lady Lovelace's fine understanding of the machine
allowed her to create the instruction routines to be fed into the computer,
making her the first female computer programmer. In the 1980's, the
U.S. Defense Department
named a programming language ADA in
her honor.

Babbage's steam-powered Engine, although ultimately never constructed, may
seem primitive by today's standards. However, it outlined the basic elements of
a modern general purpose computer and was a breakthrough concept. Consisting of
over 50,000 components, the basic design of the Analytical Engine included input
devices in the form of perforated cards containing operating instructions and a
"store" for memory of 1,000 numbers of up to 50 decimal digits long.
It also contained a "mill" with a control unit that allowed processing
instructions in any sequence, and output devices to produce printed results.
Babbage borrowed the idea of punch cards to encode the machine's instructions
from the Jacquard loom. The loom, produced in 1820 and named after its inventor,
Joseph-Marie Jacquard, used punched boards that controlled the patterns to be
woven.

In 1889, an American inventor,
Herman
Hollerith (1860-1929), also applied the Jacquard loom concept to computing.
His first task was to find a faster way to compute the
U.S. census. The previous census in 1880
had taken nearly seven years to count and with an expanding population, the
bureau feared it would take 10 years to count the latest census. Unlike
Babbage's idea of using perforated cards to instruct the machine, Hollerith's
method used cards to store data information which he fed into a machine that
compiled the results mechanically. Each punch on a card represented one number,
and combinations of two punches represented one letter. As many as 80 variables
could be stored on a single card. Instead of ten years, census takers compiled
their results in just six weeks with Hollerith's machine. In addition to their
speed, the punch cards served as a storage method for data and they helped
reduce computational errors. Hollerith brought his punch card reader into the
business world, founding Tabulating Machine Company in 1896, later to become
International Business Machines (IBM) in 1924
after a series of mergers. Other companies such as
Remington
Rand and Burroughs also manufactured punch readers for business use. Both
business and government used punch cards for data processing until the 1960's.

In the ensuing years, several engineers made other significant advances.
Vannevar Bush(1890-1974) developed a calculator for solving differential equations in
1931. The machine could solve complex differential equations that had long left
scientists and mathematicians baffled. The machine was cumbersome because
hundreds of gears and shafts were required to represent numbers and their
various relationships to each other. To eliminate this bulkiness,
John V. Atanasoff
(b. 1903), a professor at Iowa State College (now called
Iowa State University) and his graduate
student, Clifford Berry, envisioned an all-electronic computer that
applied Boolean algebra to computer circuitry. This approach was based on the
mid-19th century work of George Boole (1815-1864) who
clarified the binary system of algebra, which stated that any mathematical
equations could be stated simply as either true or false. By extending this
concept to electronic circuits in the form of on or off, Atanasoff and Berry had
developed the first all-electronic computer by 1940. Their project, however,
lost its funding and their work was overshadowed by similar developments by
other scientists.

Five Generations of Modern Computers

First Generation (1945-1956)

With the onset of the Second
World War, governments sought to develop computers to exploit their
potential strategic importance. This increased funding for computer development
projects hastened technical progress. By 1941 German engineer
Konrad Zuse had developed
a computer, the Z3, to design airplanes
and missiles. The Allied forces, however, made greater strides in developing
powerful computers. In 1943, the British completed a secret code-breaking
computer called Colossus
to decode German
messages. The Colossus's impact on the development of the computer industry
was rather limited for two important reasons. First, Colossus was not a
general-purpose computer; it was only designed to decode secret messages.
Second, the existence of the machine was kept secret until decades after the
war.

American efforts produced a broader achievement. Howard H. Aiken
(1900-1973), a Harvard engineer working with IBM, succeeded in producing an
all-electronic calculator by 1944. The purpose of the computer was to create
ballistic charts for the U.S. Navy. It was
about half as long as a football field and contained about 500 miles of wiring.
The Harvard-IBM Automatic Sequence Controlled Calculator, or Mark I for short,
was a electronic relay computer. It used electromagnetic signals to move
mechanical parts. The machine was slow (taking 3-5 seconds per calculation) and
inflexible (in that sequences of calculations could not change); but it could
perform basic arithmetic as well as more complex equations.

Another computer development spurred by the war was the Electronic Numerical
Integrator and Computer (ENIAC),
produced by a partnership between the U.S. government and the
University of Pennsylvania. Consisting
of 18,000 vacuum tubes, 70,000 resistors and 5 million soldered joints, the
computer was such a massive piece of machinery that it consumed 160 kilowatts of
electrical power, enough energy to dim the lights in an entire section of
Philadelphia.
Developed by
John
Presper Eckert (1919-1995)andJohn W. Mauchly (1907-1980),
ENIAC, unlike the Colossus and Mark I, was a general-purpose computer that
computed at speeds 1,000 times faster than Mark I.

In the mid-1940's John
von Neumann (1903-1957) joined the University of Pennsylvania team,
initiating concepts in computer design that remained central to computer
engineering for the next 40 years. Von Neumann designed the Electronic Discrete
Variable Automatic Computer (EDVAC) in
1945 with a memory to hold both a stored program as well as data. This "stored
memory" technique as well as the "conditional control transfer,"
that allowed the computer to be stopped at any point and then resumed, allowed
for greater versatility in computer programming. The key element to the von
Neumann architecture was the central processing unit, which allowed all computer
functions to be coordinated through a single source. In 1951, the
UNIVAC I
(Universal Automatic Computer), built by Remington Rand, became one of the first
commercially available computers to take advantage of these advances. Both the
U.S. Census Bureau and
General Electric owned UNIVACs. One of
UNIVAC's impressive early achievements was predicting the winner of the 1952
presidential election,
Dwight D.
Eisenhower.

First generation
computers were characterized by the fact that operating instructions were
made-to-order for the specific task for which the computer was to be used. Each
computer had a different binary-coded program called a machine language that
told it how to operate. This made the computer difficult to program and limited
its versatility and speed. Other distinctive features of first generation
computers were the use of vacuum tubes (responsible
for their breathtaking size) and magnetic drums for data storage.

Second Generation Computers (1956-1963)

By 1948, the
invention of the transistor greatly changed the
computer's development. The transistor replaced the large, cumbersome vacuum
tube in televisions, radios and computers. As a result, the size of electronic
machinery has been shrinking ever since. The transistor was at work in the
computer by 1956. Coupled with early advances in magnetic-core memory,
transistors led to second generation computers that were smaller, faster, more
reliable and more energy-efficient than their predecessors. The first
large-scale machines to take advantage of this transistor technology were early
supercomputers, Stretch by IBM and LARC by Sperry-Rand. These computers, both
developed for atomic energy laboratories, could handle an enormous amount of
data, a capability much in demand by atomic scientists. The machines were
costly, however, and tended to be too powerful for the business sector's
computing needs, thereby limiting their attractiveness. Only two LARCs were ever
installed: one in the Lawrence Radiation Labs
in Livermore, California, for which the computer was named (Livermore Atomic
Research Computer) and the other at the U.S.
Navy Research and Development Center in
Washington, D.C. Second
generation computers replaced machine language with assembly language, allowing
abbreviated programming codes to replace long, difficult binary codes.

Throughout the early 1960's, there were a number of commercially successful
second generation computers used in business, universities, and government from
companies such as Burroughs, Control Data,
Honeywell, IBM, Sperry-Rand, and
others. These second generation computers were also of solid state design, and
contained transistors in place of vacuum tubes. They also contained all the
components we associate with the modern day computer: printers, tape storage,
disk storage, memory, operating systems, and stored programs. One important
example was the IBM 1401, which was universally accepted throughout industry,
and is considered by many to be the Model T of the
computer industry.
By 1965, most large business routinely processed financial information using
second generation computers.

It was the stored program and programming language that gave computers the
flexibility to finally be cost effective and productive for business use. The
stored program concept meant that instructions to run a computer for a specific
function (known as a program) were held inside the computer's memory, and could
quickly be replaced by a different set of instructions for a different function.
A computer could print customer invoices and minutes later design products or
calculate paychecks. More sophisticated high-level languages such as
COBOL (Common Business-Oriented Language)
and FORTRAN
(Formula Translator) came into common use during this time, and have expanded to
the current day. These languages replaced cryptic binary machine code with
words, sentences, and mathematical formulas, making it much easier to program a
computer. New types of careers (programmer, analyst, and computer systems
expert) and the entire software
industry began with second generation computers.

Third Generation Computers (1964-1971)

Though transistors were clearly an improvement over the vacuum tube, they
still generated a great deal of heat, which damaged the computer's sensitive
internal parts. The quartz rock eliminated this problem.Jack Kilby, an
engineer with Texas Instruments, developed the
integrated circuit (IC) in 1958. The IC combined three electronic components
onto a small silicon disc, which was made from quartz. Scientists later managed
to fit even more components on a single chip, called a semiconductor. As a
result, computers became ever smaller as more components were squeezed onto the
chip. Another third-generation development included the use of an
operating
system that allowed machines to run many different programs at once with a
central program that monitored and coordinated the computer's memory.

Fourth Generation (1971-Present)

After the integrated circuits, the only place to go was down - in size, that
is. Large scale integration (LSI) could fit hundreds of components onto one
chip. By the 1980's, very large scale integration (VLSI) squeezed hundreds of
thousands of components onto a chip. Ultra-large scale integration (ULSI)
increased that number into the millions. The ability to fit so much onto an area
about half the size of a U.S. dime helped diminish the size and price of
computers. It also increased their power, efficiency and reliability. The
Intel 4004 chip, developed in 1971, took
the integrated circuit one step further by locating all the components of a
computer (central processing unit, memory, and input and output controls) on a
minuscule chip. Whereas previously the integrated circuit had had to be
manufactured to fit a special purpose, now one microprocessor could be
manufactured and then programmed to meet any number of demands. Soon everyday
household items such as microwave
ovens, television sets and automobiles
with electronic fuel
injection incorporated microprocessors.

Such condensed power allowed everyday people to harness a computer's power.
They were no longer developed exclusively for large business or government
contracts. By the mid-1970's, computer manufacturers sought to bring computers
to general consumers. These minicomputers came complete with user-friendly
software packages that offered even non-technical users an array of
applications, most popularly word processing and spreadsheet programs. Pioneers
in this field were Commodore,
Radio Shack and
Apple Computers. In the early
1980's, arcade
video games such as
Pac
Man and home video game
systems such as the Atari 2600 ignited consumer interest for more
sophisticated, programmable home computers.

In 1981, IBM introduced its personal computer (PC) for use in the home,
office and schools. The 1980's saw an expansion in computer use in all three
arenas as clones of the IBM PC made the personal computer even more affordable.
The number of personal computers in use more than doubled from 2 million in 1981
to 5.5 million in 1982. Ten years later, 65 million PCs were being used.
Computers continued their trend toward a smaller size, working their way down
from desktop to laptop computers (which could fit inside a briefcase) to palmtop
(able to fit inside a breast pocket). In direct competition with IBM's PC was
Apple's Macintosh line, introduced in 1984. Notable for its user-friendly
design, the Macintosh offered an operating system that allowed users to move
screen icons instead of typing instructions. Users controlled the screen cursor
using a mouse, a device that mimicked the movement of one's hand on the computer
screen.

As computers became more widespread in the workplace, new ways to harness
their potential developed. As smaller computers became more powerful, they could
be linked together, or networked, to share memory space, software, information
and communicate with each other. As opposed to a mainframe computer, which was
one powerful computer that shared time with many terminals for many
applications, networked computers allowed individual computers to form
electronic co-ops. Using either direct wiring, called a
Local Area
Network (LAN), or telephone lines, these networks could reach enormous
proportions. A global web of computer circuitry, the
Internet, for example, links
computers worldwide into a single network of information. During the 1992 U.S.
presidential election, vice-presidential candidate
Al
Gore promised to make the development of this so-called "information
superhighway" an administrative priority. Though the possibilities
envisioned by Gore and others for such a large network are often years (if not
decades) away from realization, the most popular use today for computer networks
such as the Internet is electronic mail, or E-mail, which allows users to type
in a computer address and send messages through networked terminals across the
office or across the world.

Fifth Generation (Present and Beyond)

Defining the fifth generation of computers is somewhat difficult because the
field is in its infancy. The most famous example of a fifth generation computer
is the fictional HAL9000
from Arthur
C. Clarke's novel, 2001:
A Space Odyssey. HAL performed all of the functions currently
envisioned for real-life fifth generation computers. With
artificial
intelligence, HAL could reason well enough to hold conversations with its
human operators, use visual input, and learn from its own experiences.
(Unfortunately, HAL was a little too human and had a psychotic breakdown,
commandeering a spaceship and killing most humans on board.)

Though the wayward HAL9000 may be far from the reach of real-life computer
designers, many of its functions are not. Using recent engineering advances,
computers may be able to accept spoken
word instructions and imitate human reasoning. The ability to translate a
foreign language is also a major goal of fifth generation computers. This feat
seemed a simple objective at first, but appeared much more difficult when
programmers realized that human understanding relies as much on context and
meaning as it does on the simple translation of words.

Many advances in the science of computer design and technology are coming
together to enable the creation of fifth-generation computers. Two such
engineering advances are parallel processing, which replaces von Neumann's
single central processing unit design with a system harnessing the power of many
CPUs to work as one. Another advance is
superconductor
technology, which allows the flow of electricity with little or no resistance,
greatly improving the speed of information flow. Computers today have some
attributes of fifth generation computers. For example, expert systems assist
doctors in making diagnoses by applying the problem-solving steps a doctor might
use in assessing a patient's needs. It will take several more years of
development before expert systems are in widespread use.